Indradeep Ghosh lives in Silicon Valley with his wife and two children. A few years ago, inspired in part by the film, “An Inconvenient Truth,” Ghosh began a quest to end his family’s direct consumption of fossil fuels. His goal was to do this without taking on a “minimalist lifestyle,” but to maintain his family’s current levels of comfort and convenience. Along the way, he learned a number of lessons, including many tips and tricks that can be applied by any homeowner, even those with more modest energy-efficiency goals. Ghosh shared his story with a rapt audience at the 2/7/13 meeting of the EcoGreen Group in Santa Clara.
The Ghosh household was typical of Silicon Valley, with two working adults, two school-age children and two gasoline-powered cars. Their home, built in 1997, comprises 2200 square feet, just about average for its vintage. Between the home and cars, Ghosh estimated that they were directly using the equivalent of 41,600 kilowatt hours (kWh) of energy per year. (He converted gasoline and natural gas consumption into kWh equivalents.) With a goal of “zeroing out” his electric, gas and gasoline bills, Ghosh set out to discover whether it was possible. He learned all he could about energy-efficiency and renewable energy that might be applicable to a typical middle class home. Then, he laid out four clear steps to his destination.
Ghosh needed to get an idea of how his family was using those 41,600 kWh of non-renewable energy. So, he conducted his own whole house energy audit. Using a combination of measurements from a Kill-a-Watt meter and readings from his utility meter, he developed a pie chart that showed how the family used power. (You can borrow a Kill-a-Watt meter from the local library. Here’s a link to the meter on the Santa Clara County Library website. Or if you live in Los Altos or Los Altos Hills, you can get a free online energy assessment. Check it out here. The first 50 Los Altos homeowners who sign up, will get a free assessment, courtesy of GreenTown Los Altos. All homeowners in the Town of Los Altos Hills may obtain a free online energy assessment. See the town’s sustainability page for more info.) For the Ghosh household, the biggest uses of energy were typical of a Silicon Valley home:
A Vampire in the House – Standby Power
One thing that came as a bit of a surprise was that the Ghosh home was using a total of 220W all the time, even when nothing was running. This equates to 2000kWh of electricity per year that is essentially wasted. How is that power being used? It is basically keeping certain devices ready just in case someone wants to start using them. For example, the garage door opener is always ready to receive a signal from a remote control device; a personal computer is ready to be used; or a DVR is waiting to record or play back a show instantly. This type of standby power usage, also called “vampire” or “phantom” power, is estimated by the Department of Energy to cost the average U.S. household $100 per year and accounts for more than 100 billion kWh and more than $10 billion in annual energy costs. Find out how to estimate your home’s standby power by checking out this resource from the Lawrence Berkeley Lab.
As a result of his audit, Ghosh made the following changes:
Since Ghosh was planning to power his home solely through rooftop solar panels, he needed to eliminate his home’s use of natural gas. Here’s what he did:
Replaced the gas furnace with an air source heat pump. Ghosh estimated that his gas furnace was about 80% energy efficient (i.e. uses 80% of the energy for heating the air and wastes the remaining 20%). An air source heat pump which uses electricity to move heat from one place to another would be more efficient. This was one of the most expensive retrofits due to the installation costs, which brought the total to about $8,000 ($3,000 for the system and $5,000 for installation).
The Great Debate – Gas vs. Induction Cooktop
Switching from natural gas to an induction cooktop was challenging – not because of any particular technical difficulty, but because Ghosh had to convince his wife that it would not make cooking more difficult. The induction cooktop had two disadvantages when compared to natural gas: 1) it does not heat up as quickly (However, it does heat up much faster than a standard electric cooktop.) and 2) since it runs on magnetism, it requires the use of iron or stainless steel pots and pans. (One member of the audience noted that he had purchased a 10 piece set of stainless steel pots and pans for $40 from Costco.) On the other hand, an induction cooktop is much more energy efficient and it is a much safer stove. Ghosh likes to demonstrate its safety by placing a paper towel between the cooktop and the pot and then boiling water without burning the paper towel.
The Ghosh family’s gasoline-powered cars comprised the majority of the family’s fossil fuel consumption. The family decided to keep one of their existing vehicles, a Toyota Highlander Hybrid vehicle that averages 28 MPG. This vehicle is now used only for camping trips or when large items must be transported. Ghosh purchased two new vehicles which are used for most trips, including commuting. Ghosh considered purchasing two new all-electric vehicles but compromised with his wife since she had some range anxiety (i.e. the concern that the vehicle’s electric charge will not be sufficient to go a desired distance). The Ghoshes purchased:
After Ghosh improved the energy efficiency of his home (Step 2 above), he estimated that he would need about 9,900 kWh per year to power his home and an additional 4,600 to power the two electric cars for a total power requirement of 14,500 kWh per year. A 10 kilowatt solar system would meet his needs if all his solar panels were optimally positioned and facing south. However, he had to account for several factors in sizing his system:
Ghosh has a PhD in electrical engineering and seemed to enjoy the process of designing his own system, which he says took the equivalent of three full weeks of his time. He purchased his solar panels and related equipment (e.g., inverters) online for about $3/watt (before rebates) – a significant costs savings on materials. He then had to search for a company to install the panels. The only local firm that was willing to do so was Intelisolar.
Solar is a Great Investment
It’s a safe bet that most of our readers do not have PhDs in electrical engineering or do not want to take on the design of solar power systems as a hobby. However, even paying “retail” prices for solar systems still makes sense for most homeowners. Most solar providers will: 1) develop free estimates for homeowners, 2) calculate the estimated savings and payback, and 3) offer financing options, some of which are entirely “pay as you go” plans such as leases or power purchase agreements with virtually no out-of-pocket, upfront expenditures. With federal and state tax incentives, solar power is well worth investigating.
The Ghosh family ended up reducing their total direct fossil fuel consumption (house and cars) by an estimated 65% and have eliminated their electricity, natural gas and gasoline bills (except for a very small amount of gasoline purchased for the occasional use of their Toyota Highlander hybrid vehicle).
Energy Consumption (kWh or kWh-equivalent)
|House Alone||House + Cars|
Ghosh estimated that he spent a net amount of $49,000 and expects that this will investment will be paid back in 11 years. (See table below.) Ghosh expects that the amount required for these investments will continue to decline as the benefits increase with the rising cost of power. For his family, the best investment was in the vehicles, especially given the extraordinary level of rebates and incentives.
Investments, Rebates ($000’s)
|Home Retrofit||Cars*||Solar Power||Total|
* The cost of the cars is the estimated premium paid
over the cost of similar, gasoline-powered cars.
Ghosh also recommends that homeowners calculate a statistic of kWh/square foot for their home to assess its energy efficiency. He likened this to an MPG for your home. The Ghosh home uses 4.5 kWh/square foot/year (9,900 kWh/year ÷ 2200 square feet), which compares to ratings for typical Energy Star homes on a rating scale that Ghosh compiled from various sources.
If your home uses both natural gas and electricity (true for most of us in Silicon Valley), you must first convert your natural gas usage to kWh equivalents by multiplying the therms used times a factor of 29.3 to obtain kWh. Here’s how to calculate your home’s efficiency rating:
Minimalist: 0 – 2.5
Passive House: 2.5 – 4
Energy Star: 4 – 7
Energy Conscious: 7 – 10
Most U.S. Homes: 10-20
Wasteful: over 20
4 Responses to “Produce All the Energy You Need, without Sacrificing Comfort or Convenience: How One Silicon Valley Family Did It”
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Sacrificing Comfort or Convenience: How One Silicon Valley Family Did It : GreenTown Los Altos”, exceptionally compelling plus it ended up being a terrific read.
I appreciate it,Edward
Thanks, Edward. It was interesting to calculate my own home’s energy efficiency rating. It fell into the low end of “Most US Homes” on the rating scale – but that was before we had solar panels installed.
I am surprised that the Ghosh family was able to purchase a Chevy Volt and a Ford Focus Electric for a total for $30K before rebates. I would like to know where to get such a deal.
Thank you for catching my error in this post. The $30K for the cars was what Indradeep counted as “extra cost” over and above what he estimated he would have paid for conventional gasoline-powered cars of similar size/quality. I have clarified this in the post.